1. Field of the Invention
The present invention relates to a semiconductor package connecting method and, more specifically, to a method of connecting a semiconductor package, such as a semiconductor chip, to a substrate by a wireless bonding process, particularly, a flip chip bonding process or a tape carrier bonding process, connecting wires for such a purpose, and semiconductor devices fabricated by a process employing such a connecting method.
2. Description of the Prior Art
A semiconductor package connecting method using bumps formed by a wire bonder and connecting materials for such a semiconductor package connecting method are disclosed in Japanese Patent Laid-open No. 63-301535. This known semiconductor package connecting method uses a fine alloy wire produced by quench solidifying an alloy containing Pb, Sn or In as a principal element. The tip of the alloy wire is heated to form a ball, the ball is attached to the wiring line of a semiconductor package or a substrate, and then the alloy wire is pulled off the ball to form a bump electrode on the wiring line. The semiconductor package and the substrate are connected by means of such bump electrodes.
Recently, aluminum alloys, such as Al--Si and Al--Cu--Si, have become used widely as wiring materials for semiconductor chips for their capability of suppressing electromigration and of improving the reliability of semiconductor chips. In attaching the ball directly to the aluminum alloy wiring line of a semiconductor package of a substrate by this known semiconductor package connecting method, the aluminum alloy wiring line must be heated in a flux containing CuCl.sub.2, ZnCl.sub.2, NH.sub.4 Cl, SnCl.sub.2 or HCl to remove an oxide covering the surface of the aluminum alloy wiring line, which requires an additional process and time and increases the cost of the semiconductor device.